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There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HRmax) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HRmax with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HRmax for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R2 (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HRmax explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HRmax.  相似文献   
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Our research is a response to the need to improve the understanding of the complexity of global professional communication. To investigate the complex cultural interpretations that producers and audiences apply to professional texts, we developed a two-year interactive project. Business students in New Zealand and Israel produced promotional “texts” – video clips to promote a university program – which they exchanged with their counterparts overseas to receive feedback. We adapted models of home-made visual communication and advertising which used the categories of participants, settings, topics, and style, to analyze the eight clips. Emergent findings suggested two more categories – information and language – as important analytical tools. Variables of age, gender, intra- and intercultural differences, and (cultural) context also resulted in student audiences’ multiple interpretations of the texts. The outcomes indicate the need to extend the culture-in-context approach for a “situation focused communication approach,” where the primary focus is a group of producers and their audience as they produce and interpret a professional text. This approach also foregrounds contextual variables and a plural understanding of culture to accommodate the potential for miscommunication of business and professional texts in pluricultural contexts.  相似文献   
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It has been shown that the detonation wave from a solid explosive changes in velocity after leaving the explosive. In the case of some low-velocity explosives, e.g., about 2400 metres per second, the velocity of the detonation wave increases by approximately 100–200 metres per second. With other high-velocity explosives, 5000–6000 m./sec., the velocity may decrease to around 4400 metres in some cases.Careful measurements have shown that a zone of uniform velocity exists beyond the surface of the explosive, the dimensions of the zone depending on the diameter of the sphere of the explosive or the diameter of the cartridge detonated. In the case of a 114-inch dynamite cartridge, the zone of uniform velocity extended for about ten inches, while, with a sphere of explosive four inches in diameter, the zone extended for about 25 inches.An explanation of the reason for the high velocity of the detonation wave in the gaseous medium is suggested, linking it up with either the velocity of sound at the temperatures prevailing or the kinetic velocity of the gaseous particles themselves, the latter explanation appearing to be more in accordance with the determined facts. Such an explanation implies the assumption of extremely high momentary temperatures at the wave front, in some cases of over 40,000° C. These extremely high temperatures are due partly to the heat of combustion of the explosive ingredients but more to the heating effect resulting from the enormous pressures developed at the moment of explosion, as previously applied by Berthelot and Dixon in the study of gaseous explosions. Adiabatic conditions are assumed in such calculations. With such an explanation, reasonable agreement between theory and fact is obtained for a number of explosives, and the discrepancies that exist are in cases where discrepancies might be expected.  相似文献   
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Although sabbatical leave for teachers was suggested in the James Report more than 25 years ago, it remains as much of an unattainable ideal as ever—a sad fact in the light of the message of this paper. What Les Summers tells us clearly illustrates the potential value that sabbaticals might have for teachers: how they might return to school both refreshed and with new and innovatory ideas. The chance to study some schools in Australia enabled Summers to do just this, and he was able to see issues of disaffection here from a new perspective as a result of his experiences. He then went on to develop the idea of a programme which responds to the needs of young school leavers.  相似文献   
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Significant numbers of children (6% of 11‐year‐olds) have difficulties learning to read. Meanwhile, children who receive appropriate support from their parents do better in literacy than those who do not. This study uses a case study approach to investigate how digital games designed to support struggling readers in school were used at home, by the parents of six children to support their children’s literacy. Mostly, the children enjoyed playing the games and believe that it helped improve their reading. The parents all valued the opportunity to participate in their child’s learning and believe that the games’ approach to learning is effective. The study considers key influences on the successful use of games to support struggling readers (repetition, feedback, motivation, self‐efficacy, parental beliefs) and raises questions, further consideration of which might usefully inform the future development of effective game‐based learning.  相似文献   
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